A pretensioner assembly for motor vehicle belt restraint systems is provided. The pretensioner assembly includes a tube in fluid communication with a gas generator and a driving element disposed therein that travels in a first direction in response to actuation of the gas generator. The tube includes a constriction disposed adjacent an exit of the tube. The constriction allows the driving element to pass but prevents a seal member disposed between the generator and the driving element from passing. The constriction provides backpressure on the seal member causing the seal member to expand radially outward. The system can also include a slug member disposed between the seal member and the driving element.

A seat belt device includes a spindle (11) for retracting a seat belt (13), an electric actuator (55), a pre-tensioner (14) and a power transmission mechanism (20), wherein the power transmission mechanism (20) can reversibly switch the connection and disconnection between the electric actuator (55) and the spindle (11) before the pre-tensioner (14) is activated, while when the pre-tensioner (14) is activated. The power transmission mechanism (20) non-reversibly interrupts the connection between the electric actuator (55) and the spindle (11) via an elastic piece (60) when a torque difference between an actuator-side gear (80) and a spindle-side gear (82) becomes larger than a predetermined value.

In the method for mounting an inflator (12) within a tube (14), especially of a belt tensioner, wherein an end portion (28) of the tube (14) is formed radially inwardly so that a first contact surface (30) directed to the interior of the tube (14) occurs, prior to forming an annular stabilizing disk (34) is arranged between the first contact surface (30) and a second contact surface (32) configured at the inflator (12).

A seat belt pretensioner for a seat belt device in a vehicle, the pretensioner including a frame, a ball housing attached to the frame and a drive wheel located within the ball housing. A spool is connected to the drive wheel and is fixed to one end of a seat belt webbing so that the webbing may be wound around the spool. The pretensioner further includes a pipe connected to the ball housing and a gas generator connected to the pipe. At least one power transmission element is carried in the pipe and is driven by gas provided from the gas generator to contact the drive wheel and rotate the spool to retract the seat belt. A seal member is located between the at least one power transmission element and the gas generator. The seal member is sized to plug the pipe at an inlet to the ball housing.

An extendable arm assembly includes an extendable arm structure defining a first axis, a second axis perpendicular to the first axis, and a third axis perpendicular to the first axis and the second axis. The extendable arm structure is configured to be actuated between a stowed configuration and an extended configuration in which the extendable arm structure extends along the first axis. The extendable arm structure includes a main body having a plurality of recesses and a plurality of hinge portions, and a first bladder disposed on the main body delimiting the recesses formed in the main body. The extendable arm assembly is configured to apply vacuum to the recesses to fold the main body along the hinge portions.